President Bush's service in the National Guard (search) during the Vietnam War has become a heated political issue once again, with Democrats claiming he may have been "AWOL" some of the time and the White House charging that partisan critics are just "trolling for trash."

And while the president has said he would be willing to release records that would help clear up questions about his service, White House officials are still poring over records to decide whether they will make public any more information than they already have this week.

Here, in question and answer form, is a look at the controversy.

Q: When did Bush serve?

A: He enlisted in the Texas Air National Guard at Ellington Air Force Base on May 27, 1968. The last day he was paid for Guard duty was July 30, 1973. Bush was placed on inactive Guard duty six months before his commitment ended because he was starting Harvard Business School. He was honorably discharged.

Q: What is in dispute?

A: Bush performed most of his service in Texas, but he transferred to an Alabama guard unit for a time because he was working as the political director for the Senate campaign of Winton Blount, a Bush family friend. Democrats claim Bush has not provided enough evidence that he showed up for duty in Alabama. White House officials say Bush recalls serving both in Texas and Alabama, and has provided new documents - a dental record and payroll information - from his file that they say corroborate Bush's recollections.

Q: Hasn't Bush's service record been an issue in past elections? Why is it resurfacing now?

A: Yes, it has come up previously, but the controversy was reignited earlier this month when Democratic National Committee Chairman Terry McAuliffe accused the president of being "AWOL," or absent without leave, during his time in Alabama.

Democrats are hoping to neutralize Bush's strength in the polls on national security issues by contrasting his service in the Guard, where he was a pilot who did not see combat, with that of Sen. John Kerry, the decorated Vietnam War veteran who is the front-runner for the Democratic presidential nomination. Kerry has been campaigning on his war record, often appearing with fellow veterans he likes to call his "band of brothers."

Q: When did Bush serve in Alabama?

A: Reports differ on exactly which months Bush was there, but generally, it's believed that he asked for permission to continue his duties at the 187th TAC Recon Group, Montgomery in May 1972 and returned to his Texas National Guard unit after the November election. The White House says Bush went back to Alabama again after that.

Q: Is there evidence he showed up in Alabama?

A: The White House released pay records this week that show Bush, who was a 1st lieutenant, was paid for 25 days of service between May 1972 and May 1973, the year Democrats have been questioning. The pay records, however, do not say what Bush did to receive pay, or where he did it.

Q: What other evidence is there?

A: The White House released a copy of a dental exam Bush received Jan. 6, 1973, at Dannelly Air National Guard Base in Montgomery. Democrats wonder why a dental exam was conducted at the base two months after Blount's unsuccessful election and after Bush had returned to Texas. Citing the dental record as evidence, the White House said Bush had returned to Alabama after the election to fulfill his Guard obligations.

Q: Where did the dental record come from?

A: The White House obtained the dental record, along with other medical records it did not release, from the Air Reserve Personnel Center in Denver. The record was accompanied by a statement from Dr. Richard J. Tubb, the president's current physician, who stated that he read Bush's records, which covered a period from 1968 to 1973, and concurred with the doctors' assertion that Bush was "fit" for service. "The records reflect no disqualifying medical information," Tubb said.

Q: What's next?

A: The White House, which has been hardening its defense of the president's military record, is considering whether to release more information. Democrats say all the information released so far has raised more questions than answers. They dismiss the 1973 dental record, saying they still want to see documented evidence of Bush's Guard service in Alabama in 1972.